New research suggests that liquid water may have existed on the surface of Mars as early as 200,000 years ago.

For a long time, features on Mars' surface have led scientists to speculate that liquid water existed on the planet's surface in the past, and further lines of evidence have reinforced this belief. According to new research, liquid water may have existed on the red planet as recently as 200,000 years ago, based on studies of a crater in Mars' southern hemisphere.

The results of the study, published in the international scientific journal Icarus, point to well-preserved gullies and debris from flow deposits in the crater as evidence of the action of liquid water. Co-author Andreas Johnsson and his team compared the Martian landforms with those in Svalbard, a Norwegian archipelago, to arrive at this conclusion.

"Our fieldwork on Svalbard confirmed our interpretation of the Martian deposits. What surprised us was that the crater in which these debris flows have formed is so young," says Johnsson.

Johnsson and his team determined that the crater is approximately 200,000 years old, which means that any gullies and flow deposits could not have formed any earlier than this. The most recent proposed ice age on Mars ended around 400,000 years ago, which means that the features the team examined were not formed by the melting at the end of that ice age.

Johnsson speculates that the water was formed from the melting of snow packs, when conditions on Mars were favorable for snow formation. "This is possible," he says, "since the orbital axis of Mars was more tilted in the past than it is today.

Shouldn't that be "May Have Existed as Late as 200,000 Years Ago"? The impression I've got in the past is that liquid water on Mars is generally believed to have disappeared far earlier than 200,000 years ago and the actual text of this article backs that up.

JoJo:Shouldn't that be "May Have Existed as Late as 200,000 Years Ago"? The impression I've got in the past is that liquid water on Mars is generally believed to have disappeared far earlier than 200,000 years ago and the actual text of this article backs that up.

I think the headline is trying to convey that it's at most 200,000 years - it could even be less than that.

JoJo:Shouldn't that be "May Have Existed as Late as 200,000 Years Ago"? The impression I've got in the past is that liquid water on Mars is generally believed to have disappeared far earlier than 200,000 years ago and the actual text of this article backs that up.

I think the headline is trying to convey that it's at most 200,000 years - it could even be less than that.

it should still definitely be "as late as". As early as doesn't make sense, thats saying that water exists now and didn't exist before 200,000 years ago. Exactly the opposite of what they actually mean... the escapist needs a good proofreader.

And then, the Ice Warriors came...but they all had to put on bionic suits and leave the planet. And then, there was the Mission To Mars, which wasn't a bad movie and a more current and interesting colonization project in the works.

What the report totally glosses over is the fact that for liquid water to actually be present on Mars in any form its atmospheric pressure would have had to have been about 10.0 - 15.0 psi at the surface for the water not to burn off into space....because thats why our water doesn't just evaporate out into the void over time.

The surface atmospheric pressure of Mars is about 0.087 psi, which means even if liquid water forms at all, it would immediately evaporate into the thin atmosphere and be lost, if it didn't immediately freeze into ice crystals..of course.

It also glosses over the fact that the surface temperature of Mars is currently around -55 C, liquid water requires surface level temperatures of 0 C or above to also remain fluid and not lock into ice crystals.

So the real question here isn't "Did Mars have water 200,000 years ago"...the real question is, "What happened to the atmosphere of Mars which was allowing the planet to maintain temperatures above 0C and atmospheric pressure of above 10.0 psi".

How does a planet lose its atmosphere? The principles of Atmospheric Escape can explain this to a certain degree and the surface of Mars, specifically, Olympus Mons, may help to give a few clues. But its entirely possible that Mars experienced a hydrodynamic atmospheric escape in conjunction with geothermal events such as major activity at volcanic sites such as Olympus Mons, as early as 200,000 years ago.

Course thats just me throwing ideas at the wall, but to have water, you need to have an atmosphere, and currently, Mars doesn't have much of one....so the question to me is where did the atmosphere go and why. The whole question of water on Mars, to me, has been a forgone conclusion ever since we were able to visibly see that the planet had ice caps.

Pr0:The surface atmospheric pressure of Mars is about 0.087 psi, which means even if liquid water forms at all, it would immediately evaporate into the thin atmosphere and be lost, if it didn't immediately freeze into ice crystals..of course.

It also glosses over the fact that the surface temperature of Mars is currently around -55 C, liquid water requires surface level temperatures of 0 C or above to also remain fluid and not lock into ice crystals.

You're missing that the melting point of something is a balance of atmospheric pressure and temperature, not an absolute. A much lower pressure would greatly reduce the melting point of water, as well as its evaporating point, so ice would be able to melt at a much lower temperature on Mars than it would on Earth just like it can evaporate at a lower temperature there. Mars also has much greater extremes of temperature than Earth due to the little atmosphere it has; the average temperature is around -55C, as you said, but it can get as low as -125C and as high as 20C, and these extremes would have been greater if the planet had a more tilted axis as was suggested.

So I don't see why it's impossible for liquid water to have briefly formed without the need for Earth-like conditions.

So the real question here isn't "Did Mars have water 200,000 years ago"...the real question is, "What happened to the atmosphere of Mars which was allowing the planet to maintain temperatures above 0C and atmospheric pressure of above 10.0 psi".

How does a planet lose its atmosphere? The principles of Atmospheric Escape can explain this to a certain degree and the surface of Mars, specifically, Olympus Mons, may help to give a few clues. But its entirely possible that Mars experienced a hydrodynamic atmospheric escape in conjunction with geothermal events such as major activity at volcanic sites such as Olympus Mons, as early as 200,000 years ago.

Course thats just me throwing ideas at the wall, but to have water, you need to have an atmosphere, and currently, Mars doesn't have much of one....so the question to me is where did the atmosphere go and why. The whole question of water on Mars, to me, has been a forgone conclusion ever since we were able to visibly see that the planet had ice caps.

So this study isn't asking the right questions.

Mars has no magnetic field and therefore has no protection from the ionising effect of the solar wind. Mars's atmosphere has been ripped off by the solar wind over time. Clearly there are no models on how the solar wind effects the atmosphere, the leaching happen at constant rate or are there tipping points when the atmosphere loss runs away. There is also a question of did Mar's magnetic field collapse suddenly or fade away.

So I don't see why it's impossible for liquid water to have briefly formed without the need for Earth-like conditions.

Because of the lack of atmospheric pressure to allow it to stay in liquid form, even if the mean average surface temperature allowed for water to form. So even if the water doesn't immediately lock into ice crystals, it vaporizes and is lost into space.

Mars has no magnetic field and therefore has no protection from the ionising effect of the solar wind.

This is not entirely true, Mars does not have a significant magnetic field like the Earth's which provides a shield against the solar wind but there is quite a bit of magnetic activity which is still detected by orbiters and rovers to this day. But the scientific estimate is that Mars lost its magnetic field somewhere near to 3.9 million years ago, or otherwise, about 500 million years after Mars formed as a planet, its geological magnetic field was lost because something stopped its core convection process..which has yet to be agreed on.

Now, that given, yes Mars has no protection from the ionization effect of the solar wind, nor protection from atmospheric loss and even surface water loss if all of that stuff fits together as fact...but again if all of that stuff fits together as fact, the estimate of liquid water on the surface of Mars as early as 200,000 years ago still doesn't fit....because the magnetic analysis of Mars that we do have doesn't support the planet being magnetically active up to 200,000 years ago.

So..there was no magnetic field of any significance 200,000 years ago, there was no significant atmosphere 200,000 years ago and without making a significant and generous adjustment for axial position in Martion orbital period, you can't even collaborate mean surface temperatures that allow water to exist in liquid form but again even if we tilt the orbit as suggested to allow for the right temperatures, you don't have the atmospheric pressure and you don't have a magnetic field 200,000 years ago...without either, the conditions just aren't right for liquid water.

So I don't see why it's impossible for liquid water to have briefly formed without the need for Earth-like conditions.

Because of the lack of atmospheric pressure to allow it to stay in liquid form, even if the mean average surface temperature allowed for water to form. So even if the water doesn't immediately lock into ice crystals, it vaporizes and is lost into space.

You're making no sense to me, you say that the lack of pressure wouldn't let water form, even if the temperature allowed water to form... Did you even read my post, you just seem to have repeated a summary of your first post.

I'll try my best to explain it to you again. Water can condense at lower atmospheric pressures if the temperature is low enough to compensate. Think of a canister of propane, the substances inside will be at room temperature, but exist as a liquid because the pressure inside the canister is much higher than that of the Earth's atmosphere. Releasing the propane into the lower pressure environment of the atmosphere will cause it to evaporate, but we can make the propane a liquid again if we cool it sufficiently. The same physics is true for water on Mars.

And there's none of this "immediately locking into ice crystals", either the temperature and pressure are at the correct balance for water to exist as ice, or they aren't and it will exist as another state. There is water ice at Mars' polar regions because it's cold enough there (-125) to exist as a solid despite the low pressure. If what you said was true there would be ice all over the planet, not just at the poles.

Ninmecu:So a couple 10,000 years or so before man started to become close to what we are today eh? Coincidence? I. Think. NOT!

actually it WOULD be a coincidence, cause if liquid water didn't exist in mars for over 100,000 years i wouldn't think they survived em' thereBUThttp://en.wikipedia.org/wiki/Humanidk if dogs can fly but we (as a race) appeared about 200,000 years agonow if you think about mars having 2/3 of the gravity, and an intelligent race appeared there, they'd need special physical training to survive on a wild planet like ours was 200,000 years ago, so I'd go for genetica engineering and leaving a message on our "residual" dna, which remains untouched :v